View Single Post
Old Oct 10, 2012, 10:11 PM
IBCrazy is offline
Find More Posts by IBCrazy
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
11,093 Posts
@David - Are you familiar with magnetic induction and how it works? When you have high power transmitters close to other systems, the antenna radiates an electric and a magnetic field. This field induces currents in other components due to magnetic coupling. When these currents couple with the ground wire, they effectively raise and lower the ground potential of the entire system. This phenomenon is significantly worse if you use an unbalanced antenna (the current actually travels down the coaxial cable and causes the whole transmitter case to resonate). This means interference no matter how well your components are made simply because the voltage reference is not stable.

Of course if you don't believe me, then explain how a Yagi antenna works without any coupling effect.

-Alex
IBCrazy is offline Find More Posts by IBCrazy
RCG Plus Member